Substituted anilinopyrazoles

ABSTRACT

The present invention relates to anilinopyrazole derivatives, methods for the preparation of such anilinopyrazoles, and use of such anilinopyrazoles in the treatment of certain diseases or conditions. In particular, the present invention relates to a nilinopyrazole derivatives useful as CDK2 inhibitors and use of the anilinopyrazoles in the treatment of disorders mediated by inappropriate CDK2 activity.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is filed pursuant to 35 U.S.C. § 371 as a United StatesNational Phase Application of International Application No.PCT/US2004/005615, filed Feb. 27, 2004, which claims the benefit of U.S.Provisional Application No. 60/450,365, filed Feb. 27, 2003, nowabandoned.

FIELD OF THE INVENTION

The present invention relates to anilinopyrazole derivatives, methodsfor the preparation of such anilinopyrazoles, and use of suchanilinopyrazoles in the treatment of certain diseases or conditions. Inparticular, the present invention relates to anilinopyrazole derivativesuseful as CDK2 inhibitors and use of the anilinopyrazoles in thetreatment of disorders mediated by inappropriate CDK2 activity.

BACKGROUND OF THE INVENTION

Effective chemotherapy, as well as radiotherapy, for cancer treatment,which has acceptable toxicity to normal cells, is a continuing goal inthe oncology field. Numerous cytotoxic agents are used in the treatmentof cancer, including cytotoxic agents that adversely affect rapidlydividing cells, including normal cells, that are in the process of celldivision. Typically, such agents may have effect on the cell cycle atG1—the period between mitosis and DNA synthesis; S—the period of DNAsynthesis; G2—the pre-mitotic interval; and/or M—the period of mitosisand are termed phase specific agents. Such agents are not effective inGo, the quiescent or resting cell phase. Therefore, such anti-neoplasticagents are active against cells in the process of cell division and aremost effective against cancers that have a large growth fraction, thatis, tumors that have a high percentage of dividing cells.

Protein kinases catalyze the phosphorylation of various residues inproteins including proteins involved in the regulation of cell growthand differentiation. Protein kinases play a critical role in the controlof cell growth and differentiation and are key mediators of cellularsignals leading to the production of growth factors and cytokines. See,for example, Schlessinger and Ullrich, Neuron 1992, 9, 383. The signalsmediated by protein kinases have also been shown to control growth,death and differentiation in the cell by regulating the processes of thecell cycle.

Progression through the eukaryotic cell cycle is controlled by a familyof protein kinases called cyclin dependent kinases (CDKs) and theirinteraction with a family of proteins termed cyclins (Myerson, et al.,EMBO Journal 1992, 11, 2909-17). The coordinate activation andinactivation of different cyclin/CDK complexes is necessary for normalprogression through the cell cycle (Pines, Trends in BiochemicalSciences 1993, 18, 195-7; Sherr, Cell 1993, 73, 1059-1065.). Both thecritical G1-S and G2-M transitions are controlled by the activation ofdifferent cyclin/CDK activities. In G1, both cyclin D/CDK4 and cyclinE/CDK2 are thought to mediate the onset of S-phase. Progression throughS-phase requires the activity of cyclin A/CDK2 whereas the activation ofcyclin A/cdc2 (CDK1) and cyclin B/cdc2 are required for the onset ofmetaphase. It is not surprising, therefore, that the loss of control ofCDK regulation is a frequent event in hyperproliferative diseases andcancer. (Pines, Current Opinion in Cell Biology 1992, 4, 144-8; Lees,Current Opinion in Cell Biology 1995, 7, 773-80; Hunter and Pines, Cell1994, 79,573-82).

The present invention relates to novel compounds which are effective ininhibiting CDK2. The inhibition of CDK2 should arrest cells in G1 phaseand prevent them from entering cell cycle. Thus compounds of theinvention have utility in the treatment or prevention of cancer andother hyperproliferative diseases such as psoriasis.

SUMMARY OF THE INVENTION

In a first aspect, the instant invention relates a compound of theformula I, or a salt, solvate, or a physiologically functionalderivative thereof

in which

-   R1 is hydrogen, halogen, —OMe, —OH, —NH₂, or —NHSO₂CH₃, or-   R1 is a radical of the formula

-   R2 is hydrogen, chlorine, —OMe, —OH, —NO₂, or —NH₂.

In a second aspect, the instant invention relates a method of inhibitingCDK2 protein in a mammal; comprising, administering to the mammal atherapeutically effective amount of a compound of the formula I, or asalt, solvate, or a physiologically functional derivative thereof.

In a third aspect of the present invention, there is provided apharmaceutical composition including a therapeutically effective amountof a compound of formula I, or a salt, solvate, or a physiologicallyfunctional derivative thereof and one or more of pharmaceuticallyacceptable carriers, diluents and excipients.

In a fourth aspect of the present invention, there is provided the useof a compound of formula I, or a salt, solvate, or a physiologicallyfunctional derivative thereof in the preparation of a medicament for usein the treatment or prevention of a disease caused by inappropriate cellcycle resulting from the imbalance or inappropriate activity of CDK2protein, including but not limited to, cancer and hyperproliferativediseases, such as psoriasis.

In a fifth aspect, the present invention relates to a method of treatingor preventing a disease caused by inappropriate cell cycle from theimbalance or inappropriate activity of CDK2 protein including, but notlimited to, cancer and other hyperproliferative diseases such aspsoriasis; comprising administering to a mammal a therapeuticallyeffective amount of a compound of formula I, or a salt, solvate, or aphysiologically functional derivative thereof and one or more ofpharmaceutically acceptable carriers, diluents and excipients.

In a six aspect, the present invention relates to a method of treatingor preventing cancer and other hyperproliferative diseases, such aspsoriasis; comprising administering to a mammal a therapeuticallyeffective amount of a compound of formula I, or a salt, solvate, or aphysiologically functional derivative thereof and one or more ofpharmaceutically acceptable carriers, diluents and excipients.

In a seventh aspect, the present invention relates to chemicalintermediates for making a compound of formula I.

In an eight aspect, the present invention relates to processes formaking a compound of formula I.

DETAILED DESCRIPTION

The following terms may appear in the specification. If they appear, thefollowing definitions will apply.

As used herein, the term “effective amount” means that amount of a drugor pharmaceutical agent that will elicit the biological or medicalresponse of a tissue, system, animal or human that is being sought, forinstance, by a researcher or clinician. Furthermore, the term“therapeutically effective amount” means any amount which, as comparedto a corresponding subject who has not received such amount, results inimproved treatment, healing, prevention, or amelioration of a disease,disorder, or side effect, or a decrease in the rate of advancement of adisease or disorder. The term also includes within its scope amountseffective to enhance normal physiological function.

As used herein, the term “halogen” refers to fluorine (F), chlorine(Cl), bromine (Br), or iodine (I).

As used herein, the term “optionally” means that the subsequentlydescribed event(s) may or may not occur, and includes both event(s),which occur, and events that do not occur.

As used herein, the term “physiologically functional derivative” refersto any pharmaceutically acceptable derivative of a compound of thepresent invention, for example, an ester or an amide, which uponadministration to a mammal is capable of providing (directly orindirectly) a compound of the present invention or an active metabolitethereof. Such derivatives are clear to those skilled in the art, withoutundue experimentation, and with reference to the teaching of Burger'sMedicinal Chemistry And Drug Discovery, 5th Edition, Vol 1: Principlesand Practice, which is incorporated herein by reference to the extentthat it teaches physiologically functional derivatives.

As used herein, the term “solvate” refers to a complex of variablestoichiometry formed by a solute (in this invention, a compound offormula I or a salt or physiologically functional derivative thereof)and a solvent. Such solvents for the purpose of the invention may notinterfere with the biological activity of the solute. Examples ofsuitable solvents include, but are not limited to, water, methanol,ethanol and acetic acid. Preferably the solvent used is apharmaceutically acceptable solvent. Examples of suitablepharmaceutically acceptable solvents include, without limitation, water,ethanol and acetic acid. Most preferably the solvent used is water.

As used herein, the term “substituted” refers to substitution with thenamed substituent or substituents, multiple degrees of substitutionbeing allowed unless otherwise stated.

Certain of the compounds described herein may contain one or more chiralatoms, or may otherwise be capable of existing as two enantiomers.Accordingly, the compounds of this invention include mixtures ofenantiomers as well as purified enantiomers or enantiomerically enrichedmixtures. Also included within the scope of the invention are theindividual isomers of the compounds represented by formula I above aswell as any wholly or partially equilibrated mixtures thereof. Thepresent invention also covers the individual isomers of the compoundsrepresented by the formulas above as mixtures with isomers thereof inwhich one or more chiral centers are inverted. Also, it is understoodthat all tautomers and mixtures of tautomers are included within thescope of the compounds of formula I.

Typically, the salts of the present invention are pharmaceuticallyacceptable salts. Salts encompassed within the term “pharmaceuticallyacceptable salts” refer to non-toxic salts of the compounds of thisinvention. Salts of the compounds of the present invention may compriseacid addition salts derived from a nitrogen on a substituent in thecompound of formula I. Representative salts include the following salts:acetate, benzenesulfonate, benzoate, bicarbonate, bisulfate, bitartrate,borate, bromide, calcium edetate, camsylate, carbonate, chloride,clavulanate, citrate, dihydrochloride, edetate, edisylate, estolate,esylate, fumarate, gluceptate, gluconate, glutamate,glycollylarsanilate, hexylresorcinate, hydrabamine, hydrobromide,hydrochloride, hydroxynaphthoate, iodide, isethionate, lactate,lactobionate, laurate, malate, maleate, mandelate, mesylate,methylbromide, methylnitrate, methylsulfate, monopotassium maleate,mucate, napsylate, nitrate, N-methylglucamine, oxalate, pamoate(embonate), palmitate, pantothenate, phosphate/diphosphate,polygalacturonate, potassium, salicylate, sodium, stearate, subacetate,succinate, tannate, tartrate, teoclate, tosylate, triethiodide,trimethylammonium and valerate. Other salts, which are notpharmaceutically acceptable, may be useful in the preparation ofcompounds of this invention and these form a further aspect of theinvention.

While it is possible that, for use in therapy, therapeutically effectiveamounts of a compound of formula I, as well as salts, solvates andphysiological functional derivatives thereof, may be administered as theraw chemical, it is possible to present the active ingredient as apharmaceutical composition. Accordingly, the invention further providespharmaceutical compositions, which include therapeutically effectiveamounts of compounds of the formula I and salts, solvates andphysiological functional derivatives thereof, and one or morepharmaceutically acceptable carriers, diluents, or excipients. Thecompounds of the formula I and salts, solvates and physiologicalfunctional derivatives thereof, are as described above. The carrier(s),diluent(s) or excipient(s) must be acceptable in the sense of beingcompatible with the other ingredients of the formulation and notdeleterious to the recipient thereof. In accordance with another aspectof the invention there is also provided a process for the preparation ofa pharmaceutical formulation including admixing a compound of theformula I, or salts, solvates and physiological functional derivativesthereof, with one or more pharmaceutically acceptable carriers, diluentsor excipients.

Pharmaceutical formulations may be presented in unit dose formscontaining a predetermined amount of active ingredient per unit dose.Such a unit may contain, for example, 0.5 mg to 1 g, preferably 1 mg to700 mg, more preferably 5 mg to 100 mg of a compound of the formula I,depending on the condition being treated, the route of administrationand the age, weight and condition of the patient, or pharmaceuticalformulations may be presented in unit dose forms containing apredetermined amount of active ingredient per unit dose. Preferred unitdosage formulations are those containing a daily dose or sub-dose, asherein above recited, or an appropriate fraction thereof, of an activeingredient. Furthermore, such pharmaceutical formulations may beprepared by any of the methods well known in the pharmacy art.

Pharmaceutical formulations may be adapted for administration by anyappropriate route, for example by the oral (including buccal orsublingual), rectal, nasal, topical (including buccal, sublingual ortransdermal), vaginal or parenteral (including subcutaneous,intramuscular, intravenous or intradermal) route. Such formulations maybe prepared by any method known in the art of pharmacy, for example bybringing into association the active ingredient with the carrier(s) orexcipient(s).

Pharmaceutical formulations adapted for oral administration may bepresented as discrete units such as capsules or tablets; powders orgranules; solutions or suspensions in aqueous or non-aqueous liquids;edible foams or whips; or oil-in-water liquid emulsions or water-in-oilliquid emulsions.

For instance, for oral administration in the form of a tablet orcapsule, the active drug component can be combined with an oral,non-toxic pharmaceutically acceptable inert carrier such as ethanol,glycerol, water and the like. Powders are prepared by comminuting thecompound to a suitable fine size and mixing with a similarly comminutedpharmaceutical carrier such as an edible carbohydrate, as, for example,starch or mannitol. Flavoring, preservative, dispersing and coloringagent can also be present.

Capsules are made by preparing a powder mixture, as described above, andfilling formed gelatin sheaths. Glidants and lubricants such ascolloidal silica, talc, magnesium stearate, calcium stearate or solidpolyethylene glycol can be added to the powder mixture before thefilling operation. A disintegrating or solubilizing agent such asagar-agar, calcium carbonate or sodium carbonate can also be added toimprove the availability of the medicament when the capsule is ingested.

Moreover, when desired or necessary, suitable binders, lubricants,disintegrating agents and coloring agents can also be incorporated intothe mixture. Suitable binders include starch, gelatin, natural sugarssuch as glucose or beta-lactose, corn sweeteners, natural and syntheticgums such as acacia, tragacanth or sodium alginate,carboxymethylcellulose, polyethylene glycol, waxes and the like.Lubricants used in these dosage forms include sodium oleate, sodiumstearate, magnesium stearate, sodium benzoate, sodium acetate, sodiumchloride and the like. Disintegrators include, without limitation,starch, methyl cellulose, agar, bentonite, xanthan gum and the like.Tablets are formulated, for example, by preparing a powder mixture,granulating or slugging, adding a lubricant and disintegrant andpressing into tablets. A powder mixture is prepared by mixing thecompound, suitably comminuted, with a diluent or base as describedabove, and optionally, with a binder such as carboxymethylcellulose, analiginate, gelatin, or polyvinyl pyrrolidone, a solution retardant suchas paraffin, a resorption accelerator such as a quaternary salt and/oran absorption agent such as bentonite, kaolin or dicalcium phosphate.The powder mixture can be granulated by wetting with a binder such assyrup, starch paste, acadia mucilage or solutions of cellulosic orpolymeric materials and forcing through a screen. As an alternative togranulating, the powder mixture can be run through the tablet machineand the result is imperfectly formed slugs broken into granules. Thegranules can be lubricated to prevent sticking to the tablet formingdies by means of the addition of stearic acid, a stearate salt, talc ormineral oil. The lubricated mixture is then compressed into tablets. Thecompounds of the present invention can also be combined with a freeflowing inert carrier and compressed into tablets directly without goingthrough the granulating or slugging steps. A clear or opaque protectivecoating consisting of a sealing coat of shellac, a coating of sugar orpolymeric material and a polish coating of wax can be provided.Dyestuffs can be added to these coatings to distinguish different unitdosages.

Oral fluids such as solution, syrups and elixirs can be prepared indosage unit form so that a given quantity contains a predeterminedamount of the compound. Syrups can be prepared by dissolving thecompound in a suitably flavored aqueous solution, while elixirs areprepared through the use of a non-toxic alcoholic vehicle. Suspensionscan be formulated by dispersing the compound in a non-toxic vehicle.Solubilizers and emulsifiers such as ethoxylated isostearyl alcohols andpolyoxy ethylene sorbitol ethers, preservatives, flavor additive such aspeppermint oil or natural sweeteners or saccharin or other artificialsweeteners, and the like can also be added.

Where appropriate, dosage unit formulations for oral administration canbe microencapsulated. The formulation can also be prepared to prolong orsustain the release as for example by coating or embedding particulatematerial in polymers, wax or the like.

The compounds of formula I, and salts, solvates and physiologicalfunctional derivatives thereof, can also be administered in the form ofliposome delivery systems, such as small unilamellar vesicles, largeunilamellar vesicles and multilamellar vesicles. Liposomes can be formedfrom a variety of phospholipids, such as cholesterol, stearylamine orphosphatidylcholines.

The compounds of formula I, and salts, solvates and physiologicalfunctional derivatives thereof may also be delivered by the use ofmonoclonal antibodies as individual carriers to which the compoundmolecules are coupled. The compounds may also be coupled with solublepolymers as targetable drug carriers. Such polymers can includepolyvinylpyrrolidone, pyran copolymer,polyhydroxypropylmethacrylamidephenol,polyhydroxyethylaspartamidephenol, or polyethyleneoxidepolylysinesubstituted with palmitoyl residues. Furthermore, the compounds may becoupled to a class of biodegradable polymers useful in achievingcontrolled release of a drug, for example, polylactic acid, polepsiloncaprolactone, polyhydroxy butyric acid, polyorthoesters, polyacetals,polydihydropyrans, polycyanoacrylates and cross-linked or amphipathicblock copolymers of hydrogels.

Pharmaceutical formulations adapted for transdermal administration maybe presented as discrete patches intended to remain in intimate contactwith the epidermis of the recipient for a prolonged period of time. Forexample, the active ingredient may be delivered from the patch byiontophoresis as generally described in Pharmaceutical Research, 3(6),318 (1986).

Pharmaceutical formulations adapted for topical administration may beformulated as ointments, creams, suspensions, lotions, powders,solutions, pastes, gels, sprays, aerosols or oils.

For treatments of the eye or other external tissues, for example mouthand skin, the formulations are preferably applied as a topical ointmentor cream. When formulated in an ointment, the active ingredient may beemployed with either a paraffinic or a water-miscible ointment base.Alternatively, the active ingredient may be formulated in a cream withan oil-in-water cream base or a water-in-oil base.

Pharmaceutical formulations adapted for topical administrations to theeye include eye drops wherein the active ingredient is dissolved orsuspended in a suitable carrier, especially an aqueous solvent.

Pharmaceutical formulations adapted for topical administration in themouth include lozenges, pastilles and mouth washes.

Pharmaceutical formulations adapted for rectal administration may bepresented as suppositories or as enemas.

Pharmaceutical formulations adapted for nasal administration wherein thecarrier is a solid include a coarse powder having a particle size forexample in the range 20 to 500 microns which is administered in themanner in which snuff is taken, i.e. by rapid inhalation through thenasal passage from a container of the powder held close up to the nose.Suitable formulations wherein the carrier is a liquid, foradministration as a nasal spray or as nasal drops, include aqueous oroil solutions of the active ingredient.

Pharmaceutical formulations adapted for administration by inhalationinclude fine particle dusts or mists, which may be generated by means ofvarious types of metered, dose pressurised aerosols, nebulizers orinsufflators.

Pharmaceutical formulations adapted for vaginal administration may bepresented as pessaries, tampons, creams, gels, pastes, foams or sprayformulations.

Pharmaceutical formulations adapted for parenteral administrationinclude aqueous and non-aqueous sterile injection solutions which maycontain anti-oxidants, buffers, bacteriostats and solutes which renderthe formulation isotonic with the blood of the intended recipient; andaqueous and non-aqueous sterile suspensions which may include suspendingagents and thickening agents. The formulations may be presented inunit-dose or multi-dose containers, for example sealed ampoules andvials, and may be stored in a freeze-dried (lyophilized) conditionrequiring only the addition of the sterile liquid carrier, for examplewater for injections, immediately prior to use. Extemporaneous injectionsolutions and suspensions may be prepared from sterile powders, granulesand tablets.

It should be understood that in addition to the ingredients particularlymentioned above, the formulations may include other agents conventionalin the art having regard to the type of formulation in question, forexample those suitable for oral administration may include flavouringagents.

A therapeutically effective amount of a compound of the presentinvention will depend upon a number of factors including, for example,the age and weight of the animal, the precise condition requiringtreatment and its severity, the nature of the formulation, and the routeof administration, and will ultimately be at the discretion of theattendant physician or veterinarian. However, an effective amount of acompound of formula I for the treatment or prevention of a conditioncaused by inappropriate cell cycle resulting from the imbalance orinappropriate activity of CDK2 protein, including but not limited to,cancer and hyperproliferative diseases, such as psoriasis, willgenerally be in the range of 0.1 to 100 mg/kg body weight of recipient(mammal) per day and more usually in the range of 1 to 10 mg/kg bodyweight per day. Thus, for a 70 kg adult mammal, the actual amount perday would usually be from 70 to 700 mg and this amount may be given in asingle dose per day or more usually in a number (such as two, three,four, five or six) of sub-doses per day such that the total daily doseis the same. An effective amount of a salt or solvate, orphysiologically functional derivative thereof, may be determined as aproportion of the effective amount of the compound of formula I per se.It is envisaged that similar dosages would be appropriate for treatmentof the other conditions.

Method of Preparation

Compounds of general formula I may be prepared by methods known in theart of organic synthesis as set forth in part by the following syntheticschemes, or variants thereof. In all of the schemes described below, itis well understood that protecting groups for sensitive or reactivegroups are employed where necessary in accordance with generalprinciples of chemistry. Protecting groups are manipulated according tostandard methods of organic synthesis (T. W. Green and P. G. M. Wuts(1991) Protecting Groups in Organic Synthesis, John Wiley & Sons). Thesegroups are removed at a convenient stage of the compound synthesis usingmethods that are readily apparent to those skilled in the art. Theselection of processes as well as the reaction conditions and order oftheir execution shall be consistent with the preparation of compounds offormula I. Those skilled in the art will recognize if a stereocenterexists in compounds of formula I. Accordingly, the present inventionincludes both possible stereoisomers and includes not only racemiccompounds but the individual enantiomers as well. When a compound isdesired as a single enantiomer, it may be obtained by stereospecificsynthesis or by resolution of the final product or any convenientintermediate. Resolution of the final product, an intermediate, or astarting material may be effected by any suitable method known in theart. See, for example, Stereochemistry of Organic Compounds by E. L.Eliel, S. H. Wilen, and L. N. Mander (Wiley-Interscience, 1994).

Briefly in Scheme A, a compound of formula II is reacted with dimethylcarbonate with a suitable base, such as sodium hydride, to afford acompound of formula III. A compound of formula III is subsequentlyreacted with sulfanylamide to afford a compound of formula IV. Acompound of formula IV is reacted with Lawesson's Reagent to affordthioamide of formula V which is subsequently reacted with hydrazine toafford a compound of formula I′.

In Scheme B, a compound of formula VI is reacted with sulfanylamide toafford a compound of formula VII. A compound of formula VII is reactedwith hydrazine to yield a compound of formula I″.

In Scheme C, a compound of formula VIII is reacted withsulfamoylphenylisocyanate with a base, such as LiN(TMS)₂, to afford acompound of formula IX. A compound of formula IX is reacted withhydrazine to afford a compound of formula I′″.

In Schemes A-B, R3 and R4 are R1 and R2, respectively, which are aspreviously defined, or they are groups which can be converted to R1 andR2, respectively. Conversion of R3 and R4 into respective R1 and R2 areexamplified in the actual Examples below.

SPECIFIC EMBODIMENTS—EXAMPLES

As used herein the symbols and conventions used in these processes,schemes and examples are consistent with those used in the contemporaryscientific literature, for example, the Journal of the American ChemicalSociety or the Journal of Biological Chemistry. Standard single-letteror three-letter abbreviations are generally used to designate amino acidresidues, which are assumed to be in the L-configuration unlessotherwise noted. Unless otherwise noted, all starting materials wereobtained from commercial suppliers and used without furtherpurification. Specifically, the following abbreviations may be used inthe examples and throughout the specification:

g (grams); L (liters); μL (microliters); mg (milligrams); mL(milliliters); psi (pounds per square inch); M (molar); i.v.(intravenous); MHz (megahertz); mmol (millimoles); min (minutes); mp(melting point); mM (millimolar); Hz (Hertz); mol (moles); rt (roomtemperature); h (hours); Tr (retention time); MeOH (methanol); TEA(triethylamine); TFAA (trifluoroacetic anhydride); DMSO(dimethylsulfoxide); DME (1,2-dimethoxyethane); DCE (dichloroethane);DMPU (N,N′-dimethylpropyleneurea); IBCF (isobutyl chloroformate); HOSu(N-hydxoxysuccinimide); mCPBA (meta-chloroperbenzoic acid; BOC(tert-butyloxycarbonyl); DCC (dicyclohexylcarbodiimide); Ac (acetyl);TMSE (2-(trimethylsilyl)ethyl); TIPS (triisopropylsilyl); DMAP(4-dimethylaminopyridine); ATP (adenosine triphosphate); DMEM(Dulbecco's modified Eagle medium); TLC (thin layer chromatography); RP(reverse phase); i-PrOH (isopropanol); TFA (trifluoroacetic acid); THF(tetrahydrofuran); AcOEt (ethyl acetate); DCM (dichloromethane); DMF(N,N-dimethylformamide); (CDI (1,1-carbonyldiimidazole); HOAc (aceticacid); HOBT (1-hydroxybenzotriazole); EDC (ethylcarbodiimidehydrochloride); FMOC (9-fluorenylmethoxycarbonyl); CBZ(benzyloxycarbonyl); atm (atmosphere); TMS (trimethylsilyl); TBS(t-butyldimethylsilyl); BSA (bovine serum albumin) HRP (horseradishperoxidase); HPLC (high pressure liquid chromatography); BOP(bis(2-oxo-3-oxazolidinyl)phosphinic chloride); TBAF(tetra-n-butylammonium fluoride); HBTU(O-Benzotriazole-1-yl-N,N,N′,N′-tetramethyluronium hexafluorophosphate).HEPES (4-(2-hydroxyethyl)-1-piperazine ethane sulfonic acid); DPPA(diphenylphosphoryl azide); fHNO3 (fumed HNO3); and EDTA(ethylenediaminetetraacetic acid).All references to ether are to diethyl ether; brine refers to asaturated aqueous solution of NaCl. Unless otherwise indicated, alltemperatures are expressed in ° C. (degrees Centigrade). All reactionsare conducted under an inert atmosphere at room temperature unlessotherwise noted.

¹H NMR spectra were recorded on a Brucker AVANCE-400. Chemical shiftsare expressed in parts per million (ppm, δ units). Coupling constantsare in units of hertz (Hz). Splitting patterns describe apparentmultiplicities and are designated as s (singlet), d (doublet), t(triplet), q (quartet), quint (quintet), m (multiplet), br (broad).

LC-MS were recorded on a micromass ZMD and Waters 2690. All mass spectrawere taken under electrospray ionization (ESI) methods. Most of thereactions were monitored by thin-layer chromatography on 0.25 mm E.Merck silica gel plates (60F-254), visualized with UV light, 5%ethanolic phosphomolybdic acid or p-anisaldehyde solution. Flash columnchromatography was performed on silica gel (230-400 mesh, Merck).

Example 1

4-[5-(3-Bromo-phenyl)-2H-pyrazol-3-ylamino]-benzenesulfonamide (Ia)

To a suspension of dimethyl carbonate (72 g) and 60% oily sodium hydride6.4 g at 75° C. was added 3-bromoacetophenone Ia (80 mmol, 15.9 g)dropwise. The reaction was maintained at gentle state by adjusting theaddition rate (exothemic). After the addition was complete, the reactionwas heated at 75° C. for 20 min, then cooled to rt. A small amount ofwater was added to quench the excess base and then dimethyl carbonatewas evaporated. After acidifying the residue with aqueous 10% HCl, itwas extracted with ether (2×) and the combined ether layer were washedwith water and dried. Purification by silica gel chromatography(AcOEt/Hexane=1/10) gave 17.48 g (85%) of compound IIIa.

A mixture of IIIa (10 mmol, 2.57 g) and sulfanylamide (11 mmol, 1.89 g)in toluene (30 ml) and DMF (10 ml) was heated at 130° C. for 12 h. Aftercooling to rt, the resulting precipitation was filtered and dried invacuo to give 2.18 g (55%) of IVa.

A suspension of IVa (0.49 mmol, 194 mg) and Lawesson's reagent (0.51mmol, 208 mg) in toluene (12 ml) was heated to 140° C. for 1 h, and thenconcentrated in vacuo. The residue was directly dissolved in ethanol (5mL) without any purification. Hydrazine hydrate (0.25 mL) and HOAc (afew drops) were added, and the reaction was allowed to stir at 85° C.for 12 h before it was concentrated in vacuo. The residue was extractedwith AcOEt, and AcOEt layer washed with brine, dried over Na₂SO₄.Purification by HPLC (Gilson) gave 14 mg (7.3%) of compound Ia. ¹HNMR:(400 MHz, DMSO-d6) ppm 6.44 (s, 1H), 7.06 (s, 2H), 7.42 (m, 3H), 7.55(d, 1H, J=7.6 Hz), 2H, J=8.8 Hz), 7.76 (d, 1H, J=7.6 Hz), 8.00 (t, 1H,J=1.8 Hz), 9.10 (s, 1H), 12.76 (s, 1H). LC/MS: m/z 393(M−1)⁻, 395(M+1)⁺.

Example 2

4-[5-(4-Fluoro-phenyl)-2H-pyrazol-3-ylamino]-benzenesulfonamide (Ib)

A mixture of Via (3 mmol, 642.8 mg) and sulfanylamide (3 mmol, 516.6 mg)in toluene (20 ml) and DMF (2 ml) was heated at 140° C. for 3 h, andthen concentrated in vacuo. The residue was directly dissolved inethanol (20 mL) without any purification. Hydrazine hydrate (1 mL) andHOAc (a few drops) were added, and the reaction mixture was allowed tostir at 85° C. for 12 h before it was concentrated in vacuo. The residuewas extracted with AcOEt, and AcOEt layer washed with brine, dried overNa₂SO₄. Partially evaporating the solvent gave precipitation. The solidwas collected by filtration, then recrystallized from MeOH/AcOEt, anddried in vacuo to give 111 mg (0.33 mmol, 11.1%) of compound Ib. ¹HNMR:(400 MHz, DMSO-d6) ppm 6.33 (s, 1H), 7.04 (brs, 2H), 7.31 (m, 2H), 7.43(m, 2H), 7.63 (d, 2H, J=8.8 Hz), 7.79 (dd, 2H, J=3.3, 8.6 Hz), 9.04 (s,1H), 12.64 (s, 1H). LC/MS: m/z 331(M−1)⁻, 333 (M+1) ⁺

Example 3

4-[5-(4-Bromo-phenyl)-2H-pyrazol-3-ylamino]-benzenesulfonamide (Ic)

Lithium bis(trimethylsilyl)amide (2.2 mL, 1.0 M in THF, 2.2 mmol) wasslowly added to a mixture of the corresponding acetophenone (1.0 mmol)and 4-sulfamoylphenylisocyanate (1.0 mmol, 214 mg) in dry THF (7.5 mL)at −78° C. under argon. The reaction was stirred for 30 min and thenwarmed to rt for another 12 h. It was quenched with MeOH andconcentrated in vacuo. The resultant crude thioamide was directlydissolved in ethanol (10 mL) without any purification. Hydrazine hydrate(0.5 mL) and HOAc (a few drops) were added, and the reaction mixture wasallowed to stir at 85° C. for 12 h before it was concentrated in vacuo.The residue was extracted with AcOEt, and AcOEt layer washed with brine,and dried over Na₂SO₄. Partially evaporating the solvent gaveprecipitation. The solid was collected by filtration and dried in vacuoto give 121 mg (0.307 mmol, 30.7%) of compound Ic as yellow solid.¹HNMR: (400 MHz, DMSO-d6) ppm 6.38 (s, 1H), 7.06 (brs, 2H), 7.43 (brs,2H), 7.62 ˜7.73 (m, 6H), 9.08 (s, 1H), 12.73 (s, 1H). LC/MS: m/z391(M−1)⁻, 393(M−1) ⁻, 393 (M+1)⁺, 395(M+1)⁺.

Example 4-6 compounds were made by the process as described in Example 3(Scheme C).

Example 4

4-[5-(3-Fluoro-4-methoxy-phenyl)-2H-pyrazol-3-ylamino]-benzenesulfonamide(Id)

Compound Id was obtained in 10% yield with the procedure described inExample 3. ¹HNMR: (400 MHz, DMSO-d6) ppm 3.88 (s, 3H), 6.32 (s, 1H),7.05 (brs, 2H), 7.25 (t, 1H, J=8.8 Hz), 7.43 (m, 2H), 7.55 (d, 2H, J=8.3Hz), 7.61˜7.66 (m, 3H), 9.05 (s, 1H), 12.58 (s, 1H). LC/MS: m/z361(M−1)⁻, 363 (M+1)⁺.

Example 5

4-[5-(4-Nitro-phenyl)-2H-pyrazol-3-ylamino]-benzenesulfonamide (Ie)

Compound Ie was obtained in 19% yield with the procedure described inExample 3. ¹HNMR: (400 MHz, DMSO-d6) ppm 6.61 (s, 1H), 7.08 (brs, 2H),7.40 (m, 2H), 7.66 (d, 2H, J=8.8 Hz), 8.05 (d, 2H, J=8.8 Hz), 8.32 (d,2H, J=8.8 Hz), 9.16 (s, 1H), 13.06 (s, 1H). LC/MS: m/z 358 (M−1)⁻, 360(M+1)⁺.

Example 6

4-[5-(3-Methoxy-phenyl)-2H-pyrazol-3-ylamino]-benzenesulfonamide (If)

Compound If was obtained in 37.7% yield with the procedure described inExample 3. ¹HNMR: (400 MHz, DMSO-d₆) ppm 3.82 (s, 3H), 6.36 (s, 1H),6.92 (d, 1H, J=8.1 Hz), 7.05 (brs, 2H), 7.32˜7.43 (m, 5H), 7.63 (d, 2H,J=8.8 Hz), 9.05 (s, 1H), 12.67 (s, 1 H). LC/MS: m/z 343 (M−1)⁻, 345(M+1)⁺.

Example 7

4-[5-(3-Fluoro-4-hydroxy-phenyl)-2H-pyrazol-3-ylamino]-benzenesulfonamide(Ig)

Compound Id (0.334 mmol, 121 mg) was stirred in dry CH₂Cl₂ (9 mL) at−78° C. Boron tribromide (1.67 mL, 1.0 M in CH₂Cl₂, 1.67 mmol) wasslowly added, and the reaction stirred for 12 h while warming to rt. Itwas quenched with MeOH, concentrated in vacuo. The residue was dissolvedinto 1N NaOH aqueous and filtered to remove the undissolvedprecipitation. The filtrate was neutralized with aqueous 0.1 N HCl andextracted with AcOEt. Organics were washed with brine, dried overNa₂SO₄, and concentrated in vacuo to give 58 mg (50%) of compound Ig asa white solid.

¹HNMR: (400 MHz, DMSO-d₆) ppm 6.25 (s, 1H), 6.98˜7.05 (m, 3H), 7.37˜7.42(m, 3H), 7.56 (dd, 1H, J=2.0, 12.3 Hz), 7.62 (d, 2H, J=8.8 Hz), 9.03 (s,1H), 10.14 (s, 1H), 12.33(s, 1H). LC/MS: m/z 347 (M−1)⁻, 349 (M+1)⁺.

Example 8

4-[5-(4-Amino-phenyl)-2H-pyrazol-3-ylamino]-benzenesulfonamide (Ih)

A mixture of compound Ie (0.57 mmol, 205 mg) and sodium sulfidenonahydrate (2.85 mmol, 684.5 mg) in EtOH (20 ml) and THF (10 ml) washeated to reflux for 5 h, and then concentrated in vacuo. The residuewas extracted with AcOEt, washed with brine, dried over Na₂SO₄, andtreated by BondElut SCX to give 173 mg (92%) of compound Ih. 1H NMR (400MHz, DMSO-d6) ppm 5.34 (s, 2H), 6.05 (s, 1H), 6.59 (d, 2H, J=8.6 Hz),7.03 (s, 2H), 7.38 (d, 2H, J=8.6 Hz), 7.43 (d, 2H, J=8.8 Hz), 7.61 (d,2H, J=8.8 Hz), 8.96 (s, 1H), 12.23 (s, 1H). LC/MS: m/z 328 (M−1)⁻,330(M+1)⁺.

Example 9

4-[5-(3-Hydroxy-phenyl)-2H-pyrazol-3-ylamino]-benzenesulfonamide (Ii)

Compound Ii was obtained in 42% yield with the similar procedure asdescribed Example 7 from compound If. 1H NMR (400 MHz, DMSO-d6) ppm 6.24(s, 1H), 6.76 (dd, 1H, J=1.8, 8.1 Hz), 7.05 (brs, 2H), 7.10˜7.26 (m,3H), 7.42 (d, 2H, J=8.6 Hz), 7.63 (d, 2H, J=8.8 Hz), 9.04 (s, 1H).LC/MS: m/z 329 (M−1)⁻, 331 (M+1)⁺.

Example 10

4-[5-(3-Amino-phenyl)-2H-pyrazol-3-ylamino]-benzenesulfonamide (Ij)

Compound Ij was obtained in 85% yield with the similar procedure asdescribed in Example 8 from4-[5-(3-nitro-phenyl)-2H-pyrazol-3-ylamino]-benzenesulfonamide, whichwas prepared with the similar procedure as described in Example 3. 1HNMR (400 MHz, DMSO-d6) ppm 5.19 (s, 2H), 6.12 (s, 1H), 6.55 (d, 1H, J=7.6 Hz), 6.86 (m, 2H), 7.05 (s, 2H), 7.08 (t, 1H, J=7.6 Hz), 7.44 (d,2H, J=8.8 Hz), 7.63 (d, 2H, J=8.8 Hz), 9.02 (s, 1H), 12.48 (s, 1H).LC/MS: m/z 328 (M−1) ⁻, 330 (M+1)⁺. cl Example 11

4-[5-(3-Methanesulfonylamino-phenyl)-2H-pyrazol-3-ylamino]-benzenesulfonamide(Ik)

Methylsulfonylchloride (9.2 uL, 1.05 equiv.) was added to a solution ofcompound Ij (0.1 mmol, 33 mg) in pyridine (1 mL) at 0° C. The reactionwas warmed to rt and stirred for another 4 h before it was concentratedin vacuo. A small amount of AcOEt, MeOH and CH₂Cl₂ were added to theresidue and the resultant was sonicated to give precipitation. The solidwas collected by filtration and dried in vacuo to give 21 mg (0.052mmol, 51.5%) of compound Ik. 1H NMR (400 MHz, DMSO-d6) ppm 3.06 (s, 3H),6.23 (s, 1H), 7.06 (s, 2H), 7.18 (d, 1H, J=7.1 Hz), 7.40˜7.50 (m, 5H),7.64 (d, 2H, J=8.8 Hz), 9.07 (s, 1H), 9.88 (s, 1H), 12.72 (s, 1H).LC/MS: m/z 406 (M−1)⁻, 408 (M+1)⁺.

Example 12-13 compounds were made by a similar process as described inExample 11.

Example 12

4-(5-{3-[3-(2-Fluoro-5-trifluoromethyl-phenyl)-ureido]-phenyl}-2H-pyrazol-3-ylamino)-benzenesulfonamide(Il)

Compound Il was obtained in 24.3% yield from compound Ij and1-fluoro-2-isocyanato-4-trifluoromethyl-benzene. 1H NMR (400 MHz,DMSO-d6) ppm 6.27 (s, 1H), 7.06 (s, 2H), 7.39˜7.54 (m, 7H), 7.64 (d, 2H,J=8.8 Hz), 7.79 (s, 1H), 8.64 (d, 1H, J=7.3 Hz), 9.00 (s, 1H), 9.07 (s,1H), 9.29 (s, 1H), 12.69 (s, 1H). LC/MS: m/z 533 (M−1)⁻, 535 (M+1)⁺.

4-[5-(3-Benzenesulfonylamino-phenyl)-2H-pyrazol-3-ylamino]-benzenesulfonamide(Im)

Compound Im was obtained in 44.7% yield from compound Ij andbenzenesulfonyl chloride. ¹H NMR (400 MHz, DMSO-d₆) ppm 6.15 (s, 1H),7.03 (d, 1H, J=7.8 Hz), 7.04 (brs, 2H), 7.30 (t, 1H, J=7.8 Hz),7.39˜7.43 (m, 4H), 7.54˜7.65 (m, 5H), 7.80 (d, 2H, J=8.6 Hz), 9.06 (s,1H), 10.45 (s, 1H). LC/MS: m/z 468 (M−1)⁻, 470 (M+1)⁺.

Example 14

4-[5-(3-Morpholin-4-yl-phenyl)-2H-pyrazol-3-ylamino]-benzenesulfonamide(In)

Compound Ia (0.13 mmol, 51 mg), t-BuONa (1.69 mmol, 162 mg), Pd₂(dba)₃(0.026 mmol, 23.8 mg), and [(t-BU)₃PH]BF₄ (0.01 mmol, 30 mg) were addeddry dioxane (1 mL) under argon followed by morpholine (1.3 mmol, 113 uL)and the reaction was stirred at 80° C. for 24 h. After cooling to rt,the reaction was extracted with AcOEt, and treated with BondElut SCXcolumn. Evaporating the solvent gave a residue and the product waspurified by BondElut NH2 (9% MeOH in AcOEt), which afforded compound In(17 mg, 42.5%). ¹H NMR (400 MHz, DMSO-d6) ppm 3.18 (m, 4H), 3.76 (m,4H), 6.35 (s, 1H), 6.93 (dd, 1H, J=1.8, 8.4 Hz), 7.05 (brs, 2H), 7.17(d, 1H, J=7.6 Hz), 7.27˜7.31 (m, 2H), 7.41 (d, 2H, J=7.3 Hz), 7.63 (d,2H, J=8.8 Hz), 9.03 (s, 1H), 12.61 (s, 1H). LC/MS: m/z 398 (M−1)⁻, 400(M+1)⁺.

The compounds of the present invention have valuable pharmacologicproperties. Different compounds from this class are particularlyeffective at inhibiting CDK2. Representative data is shown in Table 1following. Substrate phosphorylation assays were carried out as follows:

Cyclin dependent protein kinase 2 assays utilized the peptideBiotin-aminohexyl-ARRPMSPKKKA-NH2 (SEQ ID NO:1) as phosphoryl groupacceptor. CDK2 was expressed utilizing a baculovirus expression systemand was partially purified to comprise 20-80% of total protein, with nodetectable competing reactions present. Typically, assays were performedby incubating enzyme (0.2-10 nM), with and without inhibitor, peptidesubstrate (1-10 nM), [g-32P]ATP (1-20 nM), and 10-20 mM Mg2+ for periodsof time generally within the range 10-120 minutes. Reactions wereterminated with 0.2-2 volumes of either 20% acetic acid or 50-100 mMEDTA buffered to pH 7 (substrate consumption <20%). The buffer employedin enzyme assay was 100 mM HEPES pH 7.5 containing 0.1 mg/mL BSA and 5%DMSO. Inhibitors were diluted in 100% DMSO prior to addition into theassay. Detection of peptide phosphorylation was accomplished byscintillation counting following either collection of peptide ontophosphocellulose filters (for reactions stopped with acetic acid),collection of peptide in wells of 96 well plates coated withStreptavidin (Pierce) (reactions were stopped with EDTA), or addition ofAvidin coated Scintillant impregnated beads (Scintillation ProximityAssays from Amersham, reactions were stopped with EDTA). Counts detectedby any of these methodologies minus the appropriate background (assayswith additional 40 mM EDTA or lacking peptide substrate) were assumed tobe proportional to the reaction initial rates, and IC50s were determinedby a least squares fit to the equation CPM=Vmax*(1−([I]/(K+[I])))+nsb,or −pIC50s were determined by a fit to the equationCPM=nsb+(Vmax−nsb)/(1+(x/10x−pIC50)), where nsb are the backgroundcounts filters and washed four times with 75 mM phosphoric acid.Radioactivity was determined by liquid scintillation counting.

TABLE 1 Compound no. pIC₅₀ values Ih ++++ Ij +++ Il ++ In +

Legend pIC₅₀ values Symbol 9.99-9.0 ++++ 8.99-8.0 +++ 7.99-7.0 ++6.99-4.7 + pIC₅₀ = −log₁₀(IC₅₀)

1. A compound of the formula I, or a salt, thereof

in which R1 is hydrogen, halogen, —OMe, —OH, —NH₂, or —NHSO₂CH₃, or R1is a radical of the formula

R2 is hydrogen, chlorine, —OMe, —OH, —NO₂, or —NH₂.
 2. A pharmaceuticalcomposition comprising a therapeutically effective amount of a compoundof claim 1 and one or more of pharmaceutically acceptable carriers,diluents and excipients.
 3. A compound of claim 1 in which the halogenis bromo or fluoro.
 4. A compound of claim 1 that is4-[5-(3-bromo-phenyl)-2H-pyrazol-3-ylamino]-benzenesulfonamide.
 5. Acompound of claim 1 that is4-[5-(4-fluoro-phenyl)-2H-pyrazol-3-ylamino]-benzenesulfonamide.
 6. Acompound of claim 1 that is4-[5-(4-bromo-phenyl)-2H-pyrazol-3-ylamino]-benzenesulfonamide.
 7. Acompound of claim 1 that is4-[5-(3-fluoro-4-methoxy-phenyl)-2H-pyrazol-3-ylamino]-benzenesulfonamide.8. A compound of claim 1 that is4-[5-(4-nitro-phenyl)-2H-pyrazol-3-ylamino]-benzenesulfonamide.
 9. Acompound of claim 1 that is4-[5-(3-methoxy-phenyl)-2H-pyrazol-3-ylamino]-benzenesulfonamide.
 10. Acompound of claim 1 that is4-[5-(3-fluoro-4-hydroxy-phenyl)-2H-pyrazol-3-ylamino]-benzenesulfonamide.11. A compound of claim 1 that is4-[5-(4-amino-phenyl)-2H-pyrazol-3-ylamino]-benzenesulfonamide.
 12. Acompound of claim 1 that is4-[5-(3-hydroxy-phenyl)-2H-pyrazol-3-ylamino]-benzenesulfonamide.
 13. Acompound of claim 1 that is4-[5-(3-amino-phenyl)-2H-pyrazol-3-ylamino]-benzenesulfonamide.
 14. Acompound of claim 1 that is4-[5-(3-methanesulfonylamino-phenyl)-2H-pyrazol-3-ylamino]-benzenesulfonamide.15. A compound of claim 1 that is4-(5-{3-[3-(2-fluoro-5-trifluoromethyl-phenyl)-ureido]-phenyl}-2H-pyrazol-3-ylamino)-benzenesulfonamide.16. A compound of claim 1 that is4-[5-(3-benzenesulfonylamino-phenyl)-2H-pyrazol-3-ylamino]-benzenesulfonamide.17. A compound of claim 1 that is4-[5-(3-morpholin-4-yl-phenyl)-2H-pyrazol-3-ylamino]-benzenesulfonamide.